Claude review: drm/hibmc: Do not use cpp from struct drm_format_info

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

**Status: Good, minor nit**

Two cleanups replacing deprecated `cpp[0]` usage:

1. Line width calculation:
```c
reg = drm_format_info_min_pitch(fb->format, 0, fb->width);
```
Correct -- this is the preferred API for computing pitch from format info.

2. Format register programming:
```c
switch (fb->format->format) {
case DRM_FORMAT_XRGB8888:
    reg |= HIBMC_FIELD(HIBMC_CRT_DISP_CTL_FORMAT, 2);
    break;
case DRM_FORMAT_RGB565:
    reg |= HIBMC_FIELD(HIBMC_CRT_DISP_CTL_FORMAT, 1);
    break;
}
```

The switch has no `default` case. This is safe because `atomic_check` ensures only XRGB8888 and RGB565 reach `atomic_update`, and patch 2 restricts the format list. However, a `default: break;` or a `drm_WARN_ON_ONCE` in the default would be a minor defensive improvement. Not blocking -- this matches how other simple drivers handle it.

The absence of a Fixes/Cc:stable tag is correct since patch 2 already removed the format (RGB888) that was broken by the cpp calculation.

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Generated by Claude Code Patch Reviewer